Panel to review stormwater manual update

A development design manual update for implementing new stormwater volume controls will be reviewed tonight at a town Planning Commission hearing.

The review for a proposed resolution for Town Council adoption is the first new business item on the agenda for the meeting at 6 p.m. in the large meeting room at Town Hall, 20 Bridge St.

The town staff is recommending updating the town's Stormwater Design Manual by adding an appendix "to include recommendations for implementing volume control Best Management Practices (BMP)," according to a report by John Carmack, compliance engineer in the town's Office of Planning and Environmental Sustainability.

The new stormwater ordinance requires post-development stormwater volume to be controlled to the "maximum extent technically feasible."

The "appendix ... will provide information and methodologies for calculating the volume reduction effectiveness of rooftop structures (such as green roofs and rooftop evaporation), pervious pavement, irrigation with stormwater, rain gardens, and swales as infiltration measures," he said.

As part of its May River action plan, the council adopted stormwater volume controls on Jan. 12 as an amendment to the stormwater management ordinance. The ordinance requires adoption, by resolution, of a design manual "that provides guidance in the preparation, construction, monitoring, repair and maintenance of elements of the Stormwater Management Program."

Carmack said, "Although the town of Bluffton's current Stormwater Design Manual includes a BMP section, it does not address or suggest methodologies to calculate volume control requirements or volume BMP effectiveness that are required per the revised Stormwater Ordinance.

"Coordination and consistency in rules, regulations, and best practices is a goal of the Intergovernmental Agreement with Beaufort County with regard to environmental measures in coastal watersheds. Design requirements of the ordinance already address stormwater flow rate and water quality testing."

The Beaufort County Council adopted stormwater volume language as an appendix to the county design manual on May 10, according to Carmack.

In other business, the commission will review a renovation development plan for Bluffton Elementary School and McCracken Middle School. The plan deals with removal of mobile classrooms, formalizing two parking areas on the schools' properties on H.E. McCracken Circle, and landscaping and lighting.

Lastly, the commission will consider a tree mitigation waiver request for development of Lot 10 in Stock Farm with a commercial building. Planning staff recommends approval.

The project on the 0.23-acre lot in the development off May River Road will remove a pine tree with a 23-inch trunk diameter. The applicant seeks a waiver from town standards that would require replanting 23 trees on the property for the removal of one the pine, or payment of $8,050 to the town's tree fund if staff found there was not enough room on the property for the replacement trees, Wilson's project report says.

The development plan calls for preserving eight existing trees and planting two trees on the property.